As shown, for example, in FIG. 7, a semiconductor light emitting device emitting blue light by the prior art is formed by forming a semiconductor lamination portion 36 by laminating semiconductor layers on a sapphire substrate 31, which includes a low temperature buffer layer 32 made of GaN or the like, an n-type layer 33 made of GaN or the like, an active layer (light emitting layer) 34 made of, for example, an InGaN based (which means that a ratio of In to Ga can be varied variously and the same applies hereinafter) compound semiconductor, which has a smaller band gap than that of the n-type layer 33 and decides a wavelength of emitted light, and a p-type layer 35 made of GaN or the like; providing a p-side (upper) electrode 38 on its surface interposing a light transmitting conductive layer 37; and providing an n-side electrode 39 on a surface of the n-type layer 33 exposed by etching a part of the semiconductor lamination portion 36. Additionally, a semiconductor layer having still larger band gap energy such as an AlGaN based (which means that a ratio of Al to Ga can be varied variously and the same applies hereinafter) compound or the like may be employed on an active layer side of the n-type layer 33 and the p-type layer 35 in order to increase an effect of carrier confinement.
On the other hand, nitride semiconductor also has a refractive index of approximately 2.5 far larger than 1, which is that of air, as other compound semiconductors have. Therefore, since light generated in the light emitting layer of the nitride semiconductor layer easily reflects totally when radiating from the semiconductor lamination portion to air, much of the light is not taken out of the semiconductor lamination portion, but is apt to repeat total reflection and attenuates within the semiconductor lamination portion, and as a result, efficiency of taking light out becomes remarkably low such as an order of 10%. Then, there has been used a method for taking out light easily such that, for example, concaves and convexes are formed by etching the outermost surface of the p-type layer by dry etching into a shape of semi-cylinders each of which has a cross-sectional view of a semicircle (cf. for example PATENT DOCUMENT 1).    PATENT DOCUMENT 1: Japanese Patent Application Laid-Open No. 2000-196152